/usr/include/ostree-1/ is in libostree-dev 2016.15-5.
This file is owned by root:root, with mode 0o755.
..
/usr/include/ostree-1/ostree-async-progress.h
/usr/include/ostree-1/ostree-autocleanups.h
/usr/include/ostree-1/ostree-bootconfig-parser.h
/usr/include/ostree-1/ostree-core.h
/usr/include/ostree-1/ostree-deployment.h
/usr/include/ostree-1/ostree-diff.h
/usr/include/ostree-1/ostree-dummy-enumtypes.h
/usr/include/ostree-1/ostree-gpg-verify-result.h
/usr/include/ostree-1/ostree-mutable-tree.h
/usr/include/ostree-1/ostree-repo-deprecated.h
/usr/include/ostree-1/ostree-repo-file.h
/usr/include/ostree-1/ostree-repo.h
/usr/include/ostree-1/ostree-sepolicy.h
/usr/include/ostree-1/ostree-sysroot-upgrader.h
/usr/include/ostree-1/ostree-sysroot.h
/usr/include/ostree-1/ostree-types.h
/usr/include/ostree-1/ostree.h